Abstract

Background: Sleep Restriction Therapy (SRT) is a behavioural therapy for insomnia. Aim: To conduct a process evaluation of a randomised controlled trial comparing SRT delivered by primary care nurses plus sleep hygiene booklet with sleep hygiene booklet only for adults with Insomnia Disorder. Design and setting: Mixed methods process evaluation. Methods: We used semi-structured interviews of a purposive sample of patients receiving SRT, practice nurses delivering it, and general practitioners (GPs) or practice managers. Qualitative data were explored using Framework Analysis, and integrated with nurse comments and quantitative data, including baseline Insomnia Severity Index score and serial sleep efficiency outcomes to investigate relationships between these. Results: We interviewed 16 patients, 13 nurses, 6 practice managers and 1 GP. Patients had no previous experience of behavioural therapy, needed flexible appointment times, and preferred face-to-face consultations; nurses felt prepared to deliver SRT, accommodating patient concerns, tailoring therapy, and negotiating sleep timings, despite treatment complexity and delays between training and intervention delivery. We explored how the intervention produced change, including patient and nurse interactions and patient responses to SRT. Difficulties maintaining SRT, negative attitudes towards treatment, and low self-efficacy were highlighted. Contextual factors, including freeing GP time, time constraints and conflicting priorities for nurses, with suggestions for alternative delivery options. Participants who found SRT a positive process showed improvements in sleep efficiency, whilst those that struggled did not. Conclusion: SRT was successfully delivered by practice nurses and was generally well received by patients, despite some difficulties delivering and applying the intervention in practice.